20th TV also began notifying writers assistants Wednesday that they are being laid off effective immediately, but the studio will pay their health benefits through the end of the year, sources said.

Faced with the possibility of a partial Season 7 of "24," Fox has opted not to air the real-time drama at all this season.

"It's not a decision we wanted to make, but it's one based on how we feel the viewers expect us to schedule the show," said Preston Beckman, Fox's scheduling chief.

The decision to act quickly so early in the strike also was prompted by the large amounts of marketing money associated with the premieres of new series and the annual launch of "24." The network began airing promos for the upcoming season of "24" during the World Series and on a big screen in Times Square.

"Had we delayed executing and implementing of a strike schedule, it could've cost us a lot of money," Beckman said.

(For now, ABC is still sticking to its plan to air heavily serialized "Lost" in midseason, running the eight produced episodes, 10 short of the 18-episode order.)

Meanwhile, Fox's hit animated comedy "Family Guy" might go into repeats much sooner than scheduled if creator-exec producer Seth MacFarlane follows up on his threat not to authorize the completion of future episodes beyond the one airing Sunday.

Fox's high-profile new drama "Terminator: The Sarah Connor Chronicles," originally slated to run in tandem with "24," will now premiere Sunday, Jan. 13, and will air in "24's" Monday 9 p.m. time slot, following "Prison Break" and new reality series "When Women Ruled the World."

Fox's midseason schedule also includes new scripted series "The Return of Jezebel James," "Unhitched," "New Amsterdam" and "Canterbury's Law."

With "House" running out of original episodes, "Hell's Kitchen" has been assigned the plum post-"American Idol" Tuesday 9 p.m. slot beginning April 1, making it a British-themed reality night for Fox with "Idol" judge Simon Cowell and "Hell's" topliner Gordon Ramsey.

"We would be in original programming virtually every night of the week for the remainder of this broadcast season," News Corp. president Peter Chernin said Wednesday in a conference call with analysts. "We would expect that it would, if anything, lift our market share and have us win this season by an even greater margin than we expect to."

Fueled by "Idol," which will launch with a two-night, four-hour premiere Jan. 15-16, and helped buy the fact it only programs 15 hours a week, Fox has been considered the best equipped to handle a long writers strike.

Still, network brass are hoping to go back to their original midseason plans if the strike ends soon.

"This is a schedule that will be modified if and when there is a settlement," Beckman said.

NBC is expected to announce its revised midseason schedule shortly, while CBS and ABC are still working on theirs.

ABC on Wednesday made a minor tweak to its schedule, replacing the Nov. 20 episodes of "Cavemen" and "Carpoolers" with back-to-back "Charlie Brown" holiday specials and slotting Barbara Walters' annual "Ten Most Fascinating People" special Dec. 6, replacing a repeat of "Big Shots."

In other strike-related developments:

NBC's "The Office" officially shut down production Wednesday after its star Steve Carell and several other cast members refused to cross the picket line Monday and Tuesday, effectively bringing filming of the hit comedy to a halt. Several "Office" writers, including showrunner Greg Daniels, posted a video shot on the picket line on YouTube.

With the exception of "Scrubs," which is slated to film for awhile, all comedy series still in production are slated to wrap shooting their available scripts by early next week, followed by dramas, which will go on hiatus by the end of the month, laying off thousands of crew members.

Production on the second season of Lifetime's "Army Wives," originally scheduled to begin at the end of November, has been put on hold.